One thought: Be careful when thinking of your attempted winners as anything much different from your regular strokes. To hit with good pace and a good margin for error, you want to churn out enough topspin whenever you need it so that you (and the rest of us, too) can keep the ball down on the court. If you're thinking of going all in and doing something different whenever you try for a "winner", you might be trying to overcook it or come up with a miracle too often. Instead of winners, too many of those "different shots" can become errors.

Yes, definitely experiment with the idea of closing down your racquet face and taking a reasonable full swing through the ball. If that becomes your "rally mode" of hitting, you will have a better command of your topspin (and pace) more often. Eventually your "winners" will often be nothing more than those regular rally shots that you hit through open court once you get an opponent out of position.